Graft copolymer, thermoplastic resin composition, and molded article

Abstract

A graft copolymer (A) is obtained by graft copolymerization of a monomer component (a2) containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer in the presence of an olefin-based rubber-like polymer (a1), wherein the content of a nitrogen element in 100 mass% of the graft copolymer is more than 0 mass% and 1.5 mass% or less. Provided is a graft copolymer that, by being blended with other thermoplastic resin such as polyphenylene ether-based resin, can realize a molded article that has excellent productivity (mechanical stability) and long-term stability of quality, has excellent surface appearance, impact resistance, fluidity and heat resistance while achieving a low specific gravity, does not cause defects such as peeling, exhibits excellent functions in squeak noise suppression effect and the like, and also has radio wave characteristics.

Description

Graft copolymers, thermoplastic resin compositions, and molded articles

[0001] The present invention relates to a graft copolymer that is excellent in productivity (mechanical stability) and long-term quality stability, and when blended with other thermoplastic resins such as polyphenylene ether resins, can achieve excellent surface appearance, impact resistance, fluidity, and heat resistance, as well as low specific gravity, does not cause defects such as peeling, exhibits excellent functions such as squeaking noise suppression, and also possesses radio wave properties (dielectric properties) to realize molded articles. The present invention also relates to a thermoplastic resin composition containing this graft copolymer and a molded article formed by molding this thermoplastic resin composition.

[0002] Polyphenylene ether resins are resins that possess excellent properties in terms of heat resistance, chemical resistance, mechanical and electrical properties, and even dielectric properties. However, polyphenylene ether resins have drawbacks such as poor moldability and low impact resistance. Conventionally, a method of incorporating high-impact polystyrene (HIPS) has been known to improve the impact resistance of polyphenylene ether resins.

[0003] HIPS is a graft copolymer created by graft polymerization of styrene monomers onto a core polymer of polybutadiene or styrene-butadiene random copolymer, in order to improve the brittleness of polystyrene. Due to the poor compatibility between styrene and butadiene-based core polymers, it is difficult to increase the rubber component of the core polymer in HIPS. Therefore, in order to achieve sufficient impact resistance by increasing the rubber content, it is necessary to blend a large amount of HIPS with the polyphenylene ether resin. In this case, the heat resistance, which is a characteristic of polyphenylene ether resins, is impaired, and it becomes impossible to achieve sufficient performance.

[0004] Thus, in the technology for improving the impact resistance of polyphenylene ether resins using HIPS, there were concerns that the inherent characteristics of the polyphenylene ether resins would be compromised, thus limiting the applications and fields in which they could be used.

[0005] To resolve this problem, Patent Document 1 describes blending a graft copolymer, in which only an aromatic vinyl compound is graft copolymerized onto an ethylene-α-olefin copolymer rubber, with a polyphenylene ether resin. However, the graft copolymer of Patent Document 1 cannot sufficiently suppress the decrease in the heat resistance of the polyphenylene ether resin. Furthermore, the graft copolymer of Patent Document 1 cannot provide improvements in squeaking noise resistance or molded appearance.

[0006] Patent Document 2 describes using a graft copolymer obtained by graft copolymerizing only aromatic vinyl monomers onto an olefin-based rubbery polymer of a specific average particle size in order to improve the impact resistance of polyphenylene ether. However, the graft copolymer in Patent Document 2 has room for further improvement in terms of impact resistance and molded appearance, and also suffers from the problem of unstable quality of the graft copolymer.

[0007] Furthermore, graft copolymers used to improve the properties of other thermoplastic resins by being blended with them are desirable to have excellent compatibility with the blended thermoplastic resin. In other words, graft copolymers with poor compatibility with other thermoplastic resins may cause defects such as delamination when external forces such as tension are applied to the resulting molded product due to this poor compatibility. Moreover, compatibility with other thermoplastic resins is an important requirement for effectively obtaining improvements in impact resistance, heat resistance, etc., without impairing the surface appearance by blending with graft copolymers.

[0008] Furthermore, graft copolymers as industrial products require mechanical stability during their manufacturing process. Here, mechanical stability means, for example, that the emulsion state is less likely to break down during the pumping of latex during the manufacturing process of graft copolymers by emulsion polymerization, and that the latex exhibits excellent stability. Mechanical stability is a crucial requirement for the industrial productivity of graft copolymers.

[0009] On the other hand, in recent years, based on high-speed communication standards that utilize high frequencies of 1 GHz or higher, a new communication frequency band, development of high-frequency compatible products such as communication equipment (high-speed communication equipment) and automotive millimeter-wave sensors has been actively pursued with the aim of realizing next-generation services such as high-capacity high-speed communication and autonomous driving. In high-frequency compatible products, electromagnetic waves with frequencies of 1 GHz or higher tend to attenuate easily, so in order to improve communication distance and accuracy, it is a challenge to design materials for high-frequency transmission components such as covers and radomes that make up the product to minimize electromagnetic wave absorption loss. For example, if the dielectric properties (dielectric loss tangent and relative permittivity) of the constituent materials of these components are high, when a high-frequency signal comes into contact with the material, the high frequency is converted into heat due to dielectric loss. This reduces signal strength and communication accuracy, such as communication distance, which is a challenge. For these reasons, in recent years, there has been a demand for materials with even lower relative permittivity and dielectric loss tangent for application to high-frequency transmission components such as portable communication terminals and automotive millimeter-wave sensors based on high-speed communication standards that utilize high frequencies of 1 GHz or higher.

[0010] In response to these demands, studies have been conducted on polyphenylene ether resin compositions in which polyphenylene ether resins are alloyed with polyolefins such as polyethylene and polypropylene, or polystyrene, which have low dielectric loss tangents, in order to further improve the dielectric properties of polyphenylene ether resins.

[0011] For example, Patent Document 3 proposes a thermoplastic resin composition that is suitable for electronic components and antenna members because it has an excellent balance of heat resistance, mechanical properties, dielectric properties, moldability, and oil resistance, and comprises (A) a polyphenylene ether resin, or a mixed resin of a polyphenylene ether resin and a styrene resin, (B) a cyclic olefin resin that does not have either an aryl group or an aralkyl group, and (C) a styrene thermoplastic elastomer.

[0012] However, conventionally, no material has been provided that possesses excellent surface appearance, impact resistance, fluidity, and heat resistance, as well as superior noise suppression and radio wave characteristics such as millimeter-wave transmission. For example, in the case of radomes for vehicle-mounted millimeter-wave radars, not only are radio wave characteristics important, but the material is also prone to generating noise due to vibration and friction. Therefore, it is desirable that the material not only has excellent surface appearance, impact resistance, and heat resistance, but also superior noise suppression. However, conventionally, no material has been provided that possesses excellent surface appearance, impact resistance, and heat resistance, as well as superior radio wave characteristics and noise suppression.

[0013] International Publication No. 2019 / 004317, Japanese Patent Publication No. 2019-6976, Japanese Patent Publication No. 2023-64717

[0014] The present invention aims to solve the problems of the above-mentioned prior art and provide a graft copolymer that is excellent in productivity (mechanical stability) and long-term quality stability, and when blended with other thermoplastic resins such as polyphenylene ether resins, is excellent in surface appearance, impact resistance, fluidity, and heat resistance, and can achieve a low specific gravity, does not cause defects such as peeling, exhibits excellent functions such as squeaking noise suppression, and can also realize molded products that possess radio wave characteristics. The present invention also aims to provide a thermoplastic resin composition containing this graft copolymer and a molded product obtained by molding this thermoplastic resin composition.

[0015] The inventors of the present invention have conducted extensive research to solve the above problems and have found that the above problems can be solved by a graft copolymer (A) obtained by graft copolymerizing an olefin-based rubbery polymer with monomer components including an aromatic vinyl monomer and a vinyl cyanide monomer, wherein the nitrogen element content in 100% by mass of the graft copolymer is greater than 0% by mass and less than or equal to 1.5% by mass. Thus, the present invention has been completed. In other words, the gist of the present invention is as follows.

[0016] [1] A graft copolymer (A) obtained by graft copolymerizing a monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of an olefin-based rubbery polymer (a1), wherein the nitrogen element content in 100% by mass of the graft copolymer is greater than 0% by mass and 1.5% by mass or less.

[0017] [2] The graft copolymer (A) according to [1], wherein the olefin-based rubbery polymer (a1) comprises an ethylene-α-olefin copolymer and / or an ethylene-α-olefin-nonconjugated diene copolymer.

[0018] [3] A graft copolymer (A) according to [1] or [2], obtained by graft copolymerizing 90 to 10 parts by mass of monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of 10 to 90 parts by mass of the olefinic rubbery polymer (a1) (provided that the total of the olefinic rubbery polymer (a1) and monomer component (a2) is 100 parts by mass).

[0019] [4] A thermoplastic resin composition comprising a graft copolymer (A) described in any of [1] to [3] and another thermoplastic resin (B) other than the graft copolymer (A).

[0020] [5] The thermoplastic resin composition according to [4], wherein the content of the olefin-based rubbery polymer (a1) in 100% by mass of the thermoplastic resin composition is 2 to 30% by mass.

[0021] [6] The thermoplastic resin composition according to [4] or [5], wherein the nitrogen element content in 100% by mass of the thermoplastic resin composition is greater than 0% by mass and 6.0% by mass or less.

[0022] [7] A thermoplastic resin composition according to any one of [4] to [6], comprising 1 to 50 parts by mass of the graft copolymer (A) and 50 to 99 parts by mass of the thermoplastic resin (B) (provided that the total of the graft copolymer (A) and the thermoplastic resin (B) is 100 parts by mass).

[0023] [8] The thermoplastic resin composition according to any one of [4] to [7], wherein the thermoplastic resin (B) comprises one or more selected from the group consisting of polyphenylene ether resins, polystyrene resins, polycarbonate resins, polyacrylic resins, polyamide resins, and polyester resins.

[0024] [9] A molded article comprising a thermoplastic resin composition according to any one of [4] to [8].

[0025]

[10] High-speed communication equipment components including the molded products described in [9].

[0026]

[11] A radome including the molded article described in [9].

[0027]

[12] A millimeter-wave radome consisting of the radomes described in

[11] .

[0028]

[13] A millimeter-wave radar equipped with the millimeter-wave radome described in

[12] .

[0029] The graft copolymer (A) of the present invention exhibits excellent productivity (mechanical stability) and long-term quality stability, as well as excellent compatibility with other thermoplastic resins. Furthermore, the thermoplastic resin composition of the present invention, obtained by blending this graft copolymer (A) with other thermoplastic resins such as polyphenylene ether resins, provides molded articles that exhibit excellent surface appearance, impact resistance, fluidity, and heat resistance, as well as low specific gravity, without causing defects such as peeling, and furthermore, exhibit excellent functions such as squeaking noise suppression, and also possess radio wave characteristics such as millimeter wave transmission. Accordingly, the graft copolymer (A) and thermoplastic resin composition of the present invention can provide molded articles with excellent various properties and functionalities, and high commercial value.

[0030] In particular, a molded article formed of the thermoplastic resin composition of the present invention is excellent in surface appearance, impact resistance, fluidity, and heat resistance, has a low specific gravity, is excellent in squeak noise suppression effect, and also has radio wave characteristics in a high frequency band such as millimeter-wave transmissivity. Therefore, it is possible to provide various high-speed communication device components such as high-quality and highly reliable millimeter-wave radomes and millimeter-wave radars. High-speed communication device components such as millimeter-wave radomes using the molded article of the present invention have both a squeak noise suppression effect and radio wave characteristics such as millimeter-wave transmissivity. Therefore, they are extremely useful as various high-speed communication device components such as radomes for vehicle-mounted millimeter-wave radars, which are prone to generate squeak noise when subjected to vibration and friction.

[0031] Embodiments of the present invention are described in detail below.

[0032] In the present specification, the term "unit" means a structural portion contained in a polymer that is derived from a compound (monomer) before polymerization. For example, "α-olefin unit" means "a structural portion derived from α-olefin and contained in a polymer". The content of monomer units in each polymer corresponds to the amount of the monomer used in producing the polymer.

[0033] [Graft Copolymer (A)] The graft copolymer (A) of the present invention is a graft copolymer obtained by graft copolymerizing a monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of an olefin-based rubbery polymer (a1), and is characterized in that the content of nitrogen element in 100% by mass of the graft copolymer is more than 0% by mass and 1.5% by mass or less.

[0034] <Mechanism> The inventors have obtained the following findings as a result of their studies. Normally, graft copolymers immediately after graft copolymerization by emulsion polymerization are pumped to the solidification process. At this time, if the nitrogen element content in the graft copolymer is within the range specified by the present invention, the emulsion state is less likely to break down, and the mechanical stability of the latex is high. Furthermore, by using a vinyl cyanide monomer together with an aromatic vinyl monomer as monomer components used in graft copolymerization, the stability during pump transfer of the latex is further improved, the generation of foreign matter is suppressed, and adverse effects on the surface appearance of the molded product due to foreign matter are prevented. In addition, graft copolymers with a nitrogen element content within the range specified by the present invention also have excellent compatibility with other thermoplastic resins such as polyphenylene ether resins. Therefore, by coexisting a vinyl cyanide monomer with an aromatic vinyl monomer in the graft copolymer system and keeping the nitrogen element content within the range specified in the present invention, a graft copolymer (A) with stable product quality can be produced with high productivity. Furthermore, according to the thermoplastic resin composition of the present invention, in which such a graft copolymer (A) is blended with another thermoplastic resin (B), it is possible to achieve excellent surface appearance, impact resistance, fluidity, and heat resistance, as well as low specific gravity, without causing defects such as peeling, and furthermore, to realize a molded product that exhibits excellent functions such as squeaking noise suppression, and also possesses radio wave characteristics.

[0035] In contrast, among the aforementioned Patent Documents 1 to 3, Patent Documents 1 and 2, which describe graft copolymers, only describe aromatic vinyl monomers as monomer components for graft copolymerization. Furthermore, Patent Documents 1 and 2 do not describe specifying the nitrogen element content in the graft copolymer, nor do they offer any suggestions regarding the control of nitrogen element content, mechanical stability in emulsion polymerization using cyanide-based vinyl monomers, the generation of foreign matter, or compatibility with other thermoplastic resins.

[0036] <Olefin-based rubbery polymer (a1)> In the graft copolymer (A) of the present invention, examples of the olefin-based rubbery polymer (a1) used as the rubbery polymer include ethylene-α-olefin copolymers, ethylene-propylene-non-conjugated diene copolymers, and the like.

[0037] As the α-olefin of the ethylene-α-olefin copolymer, one or more selected from propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-icosene, 1-docosene and the like can be mentioned. Among these, from the viewpoint of impact resistance of a molded article obtained from the thermoplastic resin composition of the present invention that contains the graft copolymer (A) of the present invention (hereinafter sometimes simply referred to as "obtained molded article"), α-olefins having 3 to 20 carbon atoms are preferred, and propylene is particularly preferred.

[0038] The content of ethylene units in the ethylene-α-olefin copolymer is preferably 45 to 65% by mass, more preferably 50 to 60% by mass, when the total of all constituent units constituting the ethylene-α-olefin copolymer is taken as 100% by mass. When the content of ethylene units is within the above range, the balance of squeak noise resistance, radio wave characteristics and impact resistance of the obtained molded article is further improved. In particular, when the content of ethylene units is 50 to 60% by mass, the squeak noise suppression effect, impact resistance, radio wave characteristics and low-temperature impact resistance of the obtained molded article are further improved.

[0039] The ethylene-propylene-non-conjugated diene copolymer is a copolymer composed of ethylene units, propylene units, and non-conjugated diene units as a third component. Examples of the non-conjugated diene include one or more selected from dicyclopentadiene, ethylidene norbornene, 1,4-hexadiene, 1,5-hexadiene, 2-methyl-1,5-hexadiene, 1,4-cycloheptadiene, 1,5-cyclooctadiene and the like.

[0040] The mass average molecular weight (Mw) of the olefin-based rubbery polymer (a1) is usually 17×10 ４ to 35×10 ４ , and 26×10 ４ to 32×10４ Preferably, the mass-average molecular weight (Mw) of the olefin-based rubbery polymer (a1) is 17 × 10 ４ If it is smaller than this, the resulting molded product will have inferior noise resistance, radio wave characteristics, and shock resistance. On the other hand, if the mass-average molecular weight (Mw) is 35 × 10 ４ If the mass average molecular weight (Mw) is greater than 26 × 10, the fluidity of the thermoplastic resin composition obtained by incorporating the graft copolymer (A) of the present invention (hereinafter sometimes simply referred to as "the obtained thermoplastic resin composition") and the surface appearance of the resulting molded article tend to be inferior. ４ ~32 x 10 ４ In that case, the resulting thermoplastic resin composition will have better fluidity, and the resulting molded article will have superior surface appearance, noise resistance, radio wave characteristics, and impact resistance.

[0041] The molecular weight distribution (Mw / Mn) of the olefin-based rubbery polymer (a1) is 1 to 3, preferably 1.9 to 2.5. When the molecular weight distribution (Mw / Mn) is greater than 3, the resulting molded article tends to have inferior squeaking noise resistance, radio wave characteristics, and impact resistance. When the molecular weight distribution (Mw / Mn) is 1.9 to 2.5, the resulting thermoplastic resin composition has even better fluidity, and the resulting molded article has even better surface appearance, squeaking noise suppression effect, radio wave characteristics, and impact resistance.

[0042] Here, the mass-average molecular weight (Mw) and number-average molecular weight (Mn) of the olefin-based rubbery polymer (a1) are measured using gel permeation chromatography (GPC) and converted to values ​​equivalent to standard polystyrene. Specifically, they are measured by the following method.

[0043] <Method for measuring mass-average molecular weight (Mw) and molecular weight distribution (Mw / Mn)> Using GPC (GPC: Waters "GPC / V2000", column: Showa Denko "Shodex AT-G + AT-806MS"), the mass-average molecular weight (Mw) and number-average molecular weight (Mn) in polystyrene equivalent are measured using o-dichlorobenzene (145°C) as the solvent, and the molecular weight distribution (Mw / Mn) is calculated.

[0044] The method for producing the olefin-based rubbery polymer (a1) is not limited. For example, ethylene-α-olefin copolymers are usually produced by polymerizing ethylene and α-olefin using a metallocene catalyst or a Ziegler-Natta catalyst.

[0045] Examples of metallocene catalysts include catalysts that combine metallocene complexes, in which organic compounds having a cyclopentadienyl skeleton or halogen atoms are coordinated to transition metals (zirconium, titanium, hafnium, etc.), with organoaluminum compounds, organoboron compounds, etc. Examples of Ziegler-Natta catalysts include catalysts that combine halides of transition metals (titanium, vanadium, zirconium, hafnium, etc.) with organoaluminum compounds, organoboron compounds, etc.

[0046] One polymerization method involves copolymerizing ethylene and α-olefin in a solvent in the presence of the catalyst. Examples of solvents include hydrocarbon solvents (benzene, toluene, xylene, pentane, hexane, heptane, octane, etc.). The hydrocarbon solvent may be used alone or in a mixture of two or more. Alternatively, the α-olefin raw material may be used as the solvent.

[0047] By changing the supply amounts of ethylene and α-olefin, the type and amount of molecular weight regulators such as hydrogen, the type and amount of catalyst, the reaction temperature, pressure, and other reaction conditions, the ethylene unit content, mass-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the ethylene-α-olefin copolymer can be adjusted.

[0048] Ethylene-propylene-non-conjugated diene copolymers can also be produced in the same manner as described above, using ethylene and propylene along with a non-conjugated diene.

[0049] By using such an olefin-based rubber-like polymer (a1), the resulting molded products are expected to have good weather resistance and abrasion resistance, reduced friction coefficient and squeaking noise, and improved radio wave characteristics. Furthermore, it is expected that discoloration and deterioration of physical properties of molded products in high-temperature environments will be suppressed, and the amount of flame retardant added to flame-retardant materials will be reduced. In addition, improved electrical properties and chemical resistance can also be expected.

[0050] The olefin-based rubbery polymer (a1) may be an aqueous dispersion. The method for preparing the aqueous dispersion of the olefin-based rubbery polymer (a1) is not limited. For example, the following methods (1) or (2) can be used: (1) Melt-knead the olefin-based rubbery polymer (a1) using a known melt-kneading means (kneader, Banbury mixer, multi-screw extruder, etc.), disperse it by applying mechanical shear force, and add it to an aqueous medium containing an emulsifier. (2) Dissolve the olefin-based rubbery polymer (a1) together with an emulsifier in a hydrocarbon solvent (pentane, hexane, heptane, benzene, toluene, xylene, etc.), add it to an aqueous medium to emulsify it, stir it thoroughly, and then distill off the hydrocarbon solvent. When preparing the aqueous dispersion of the olefin-based rubbery polymer (a1), emulsifiers, acid-modified olefin polymers, etc., may be added as other components.

[0051] Examples of emulsifiers include those that are known. Examples of emulsifiers include one or more of long-chain alkyl carboxylates, alkyl sulfosuccinates, and alkylbenzene sulfonates. The amount of emulsifier added is preferably 1 to 8 parts by mass per 100 parts by mass of olefin-based rubbery polymer (a1), in order to suppress thermal discoloration of the resulting thermoplastic resin composition and to facilitate control of the particle size of the olefin-based rubbery polymer (a1) in the aqueous dispersion.

[0052] Examples of acid-modified olefin polymers include olefin polymers (such as polyethylene and polypropylene) with a mass-average molecular weight of 1,000 to 5,000, modified with a compound having a functional group (such as an unsaturated carboxylic acid compound). Examples of unsaturated carboxylic acid compounds include acrylic acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, and maleic acid monoamide. The acid value of the acid-modified olefin polymer is preferably about 10 to 50 mg-KOH / g. The acid-modified olefin polymer may be used alone or in combination of two or more types.

[0053] The amount of acid-modified olefin polymer added is preferably 1 to 40 parts by mass per 100 parts by mass of olefin-based rubbery polymer (a1). If the amount of acid-modified olefin polymer added is within the above range, the balance between scratch resistance and impact resistance of the resulting molded product will be even better.

[0054] The method of adding the acid-modified olefin polymer is not limited. For example, when using an olefin-based rubbery polymer (a1) after crosslinking treatment as described below, the following methods (1) or (2) can be used. (1) The olefin-based rubbery polymer (a1) and the acid-modified olefin polymer are mixed and then crosslinked. (2) The olefin-based rubbery polymer (a1) and the acid-modified olefin polymer are crosslinked separately and then mixed. The method of mixing the olefin-based rubbery polymer (a1) and the acid-modified olefin polymer is not limited. Mixing methods include melt kneading using a kneader, Banbury mixer, multi-screw extruder, etc.

[0055] As the aqueous medium for the aqueous dispersion of the olefin-based rubbery polymer (a1), water or an aqueous solution of a basic substance can be used.

[0056] The olefin-based rubbery polymer (a1) may also be crosslinked.

[0057] By crosslinking the olefin-based rubber polymer (a1), the resulting molded product exhibits an even better balance of impact resistance, color development, noise suppression, and radio wave characteristics.

[0058] The gel content of the crosslinked olefin-based rubbery polymer (a1) is preferably 35 to 75% by mass, more preferably 40 to 70% by mass, and particularly preferably 45 to 65% by mass, from the viewpoint of balancing the scratch resistance, impact resistance, cold impact resistance, color development, and lubricity of the resulting molded article. The specific method for measuring the gel content of the crosslinked olefin-based rubbery polymer (a1) is as follows.

[0059] <Method for Measuring Gel Content> A 0.5 g sample of solidified powder [Cx] obtained by adding dilute sulfuric acid to an aqueous dispersion of a cross-linked olefin-based rubbery polymer (a1), washing with water, and drying, is immersed in 200 mL of toluene at 110°C for 5 hours. The residue is then filtered through a 200-mesh wire mesh and dried. The mass of the obtained dried product [Cy] is measured, and the gel content of the cross-linked olefin-based rubbery polymer (a1) is calculated using the following formula (1): Gel content (%) = Amount of dry substance [Cy] (g) / Mass of solidified powder sample [Cx] (g) × 100 …(1)

[0060] The olefin-based rubbery polymer (a1) can be crosslinked by known methods. Examples of crosslinking methods include the following (i) or (ii): (i) A method of crosslinking the olefin-based rubbery polymer (a1) by adding an organic peroxide and, if necessary, a polyfunctional compound; (ii) A method of crosslinking using ionizing radiation. From the viewpoint of impact resistance and color development of the resulting molded article, method (i) is preferred.

[0061] (i) Specifically, the method involves adding an organic peroxide and, if necessary, a polyfunctional compound to an olefin-based rubbery polymer (a1) or an aqueous dispersion thereof, and then heating the mixture.

[0062] The gel content of the crosslinked olefin-based rubbery polymer (a1) can be adjusted by controlling the amount of organic peroxide and polyfunctional compound added, the heating temperature, the heating time, etc. The heating temperature varies depending on the type of organic peroxide. The heating temperature is preferably in the range of -5°C to +30°C relative to the 10-hour half-life temperature of the organic peroxide. The heating time is preferably 3 to 15 hours.

[0063] The organic peroxide is used to form a crosslinked structure in the olefin-based rubbery polymer (a1). Examples of organic peroxides include peroxyester compounds, peroxyketal compounds, dialkyl peroxide compounds, and hydroperoxide compounds. The organic peroxide may be used alone or in combination of two or more types.

[0064] Specific examples of peroxyester compounds include α,α'-bis(neodecanoylperoxy)diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-hexylhexanoate, and t-butylperoxy Examples include oxy-2-hexylhexanoate, t-butyl peroxyisobutyrate, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxymalic acid, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, 2,5-dimethyl-2,5-bis(m-toluylperoxy)hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butyl peroxyacetate, t-butyl peroxy-m-toluylbenzoate, t-butyl peroxybenzoate, and bis(t-butylperoxy)isophthalate.

[0065] Specific examples of peroxyketal compounds include 1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 2,2-bis(t-butylperoxy)butane, n-butyl4,4-bis(t-butylperoxy)valerate, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane.

[0066] Specific examples of dialkylperoxide compounds include α,α'-bis(t-butylperoxide)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyn-3.

[0067] Specific examples of hydroperoxide compounds include cumene hydroperoxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide.

[0068] As organic peroxides, dialkyl peroxide compounds such as dicumyl peroxide, t-butylcumyl peroxide, and di-t-butyl peroxide are particularly preferred because they allow for easy adjustment of the gel content of the crosslinked olefin-based rubbery polymer (a1).

[0069] The amount of organic peroxide added is preferably 0.1 to 5 parts by mass per 100 parts by mass of the olefin-based rubbery polymer (a1), as this makes it easy to adjust the gel content of the crosslinked olefin-based rubbery polymer (a1) to a range of 35 to 75% by mass.

[0070] The polyfunctional compound is used in combination with an organic peroxide as needed to adjust the gel content of the crosslinked olefin-based rubbery polymer (a1). Examples of polyfunctional compounds include divinylbenzene, allyl methacrylate, ethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, tetraethylene glycol diacrylate, triallyl cyanurate, triallyl isocyanurate, and pentaerythritol tetraacrylate. Divinylbenzene is preferred as the polyfunctional compound because it is easy to adjust the gel content. The polyfunctional compound may be used alone or in combination of two or more.

[0071] The amount of the polyfunctional compound added is preferably 10 parts by mass or less per 100 parts by mass of the olefin-based rubbery polymer (a1), as this makes it easier to adjust the gel content of the crosslinked olefin-based rubbery polymer (a1) to 35 to 75% by mass.

[0072] The average particle size of the olefin-based rubbery polymer (a1) used in the present invention is preferably 0.1 to 1.0 μm, more preferably 0.15 to 0.8 μm, even more preferably 0.2 to 0.7 μm, and particularly preferably 0.25 to 0.6 μm. If the average particle size is within the above range, the resulting molded product will have excellent impact resistance and surface appearance. If the average particle size is within the above range, the squeaking noise suppression effect will also be stably exhibited.

[0073] Here, the specific method for measuring the average particle size of the olefin-based rubbery polymer (a1) is as shown in the Examples section below.

[0074] The olefin-based rubbery polymer (a1) may be used alone, or two or more types with different monomer compositions and physical properties may be mixed and used.

[0075] <Monomer component (a2)> The graft copolymer (A) of the present invention is obtained by graft copolymerizing a monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of the above-mentioned olefin-based rubbery polymer (a1). As described above, the olefin-based rubbery polymer (a1) may or may not be crosslinked.

[0076] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, and o,p-dichlorostyrene. Among these, styrene and α-methylstyrene are preferred. These aromatic vinyl monomers may be used individually or in combination of two or more.

[0077] Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, and ethacrylonitrile. Among these, acrylonitrile is preferred. These vinyl cyanide monomers may be used individually or in combination of two or more.

[0078] By using an aromatic vinyl monomer as the monomer for graft copolymerization with an olefin-based rubbery polymer (a1), the resulting thermoplastic resin composition exhibits good fluidity, resulting in a good surface appearance of the molded product. Furthermore, by using a vinyl cyanide monomer, as mentioned above, the generation of foreign matter is suppressed during manufacturing, especially in the case of emulsion polymerization, and stability is improved when pumping the latex, thus maintaining product quality. In addition, by using a vinyl cyanide monomer, the quality of the resulting graft copolymer (A) is stable and contains fewer foreign matter, so stable performance is exhibited when compounded with other thermoplastic resins (B), and the surface appearance of the molded product is also improved.

[0079] <Graft Components> Graft copolymer (A) is preferably obtained by graft copolymerizing 90 to 10 parts by mass of monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of 10 to 90 parts by mass of olefin-based rubbery polymer (a1), more preferably obtained by graft copolymerizing 60 to 15 parts by mass of monomer component (a2) in the presence of 40 to 85 parts by mass of olefin-based rubbery polymer (a1), even more preferably obtained by graft copolymerizing 40 to 20 parts by mass of monomer component (a2) in the presence of 60 to 80 parts by mass of olefin-based rubbery polymer (a1), and particularly preferably obtained by graft copolymerizing 35 to 25 parts by mass of monomer component (a2) in the presence of 65 to 75 parts by mass of olefin-based rubbery polymer (a1). However, the total of olefin-based rubbery polymer (a1) and monomer component (a2) shall be 100 parts by mass. If the proportion of the olefin-based rubbery polymer (a1) is within the above range, the productivity of the graft copolymer (A) is good, and the resulting molded product has good impact resistance and surface appearance. Furthermore, if the proportion of the olefin-based rubbery polymer (a1) is within the above range, the resulting molded product has a good molded appearance, and improvements in impact strength, reduction of squeaking noise, and radio wave characteristics are effectively exhibited.

[0080] Here, monomer component (a2) is a monomer component containing an aromatic vinyl monomer and a vinyl cyanide monomer, and the ratio of aromatic vinyl monomer to vinyl cyanide monomer in 100% by mass of monomer component (a2) is preferably aromatic vinyl monomer / vinyl cyanide monomer = 90-99.9% by mass / 10-0.1% by mass, more preferably 93-99.5% by mass / 7-0.5% by mass, and even more preferably 95-99% by mass / 5-1% by mass, from the viewpoint of moldability and the appearance of the molded product. If the proportion of vinyl cyanide monomer is higher or lower than the above range, it may be difficult to keep the nitrogen element content of the graft copolymer (A) of the present invention within the specified range of the present invention. In this case, it becomes difficult to obtain the effects of the graft copolymer (A) of the present invention containing nitrogen elements in a predetermined proportion.

[0081] In addition to aromatic vinyl monomers and vinyl cyanide monomers, monomer component (a2) may contain 0 to 10% by mass of other vinyl monomers copolymerizable with these monomers in 100% by mass. Examples of other vinyl monomers copolymerizable with these monomers include, but are not limited to, one or more unsaturated carboxylic acid ester monomers such as methyl (meth)acrylate, maleimide monomers such as N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide (maleimide monomers may also include maleimide monomers used as copolymerization components for polyacrylic resins described later), unsaturated dicarboxylic acids such as maleic acid, unsaturated dicarboxylic acid anhydrides such as maleic anhydride, or unsaturated amides such as acrylamide. Even when these copolymerizable vinyl monomers are included, it is preferable that the ratio of aromatic vinyl monomers to vinyl cyanide monomers be within the aforementioned range. However, when using a compound containing nitrogen elements, such as a maleimide compound, as another copolymerizable vinyl monomer, the nitrogen element content of the graft copolymer (A) of the present invention should be adjusted to be within the range specified by the present invention.

[0082] <Method for producing graft copolymer (A)> The method for producing graft copolymer (A) is not limited. Graft copolymer (A) can be produced by known polymerization methods (emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization). As the method for producing the graft copolymer of the present invention, emulsion polymerization is particularly preferred in terms of productivity through control of the amount of rubber and combination of compositions.

[0083] As a method for producing the graft copolymer (A) by emulsion polymerization, for example, an organic peroxide is mixed with a monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer, and then continuously added to an aqueous dispersion of an olefin-based rubbery polymer (a1) or a crosslinked olefin-based rubbery polymer (a1). The organic peroxide is preferably used as a redox initiator, which is a combination of an organic peroxide, a transition metal, and a reducing agent. During graft copolymerization, chain transfer agents, emulsifiers, etc., may be used as needed.

[0084] As a redox initiator, a combination of an organic peroxide and a ferrous sulfate-chelating agent is preferred because it does not require the polymerization reaction conditions to be at high temperatures, avoids degradation of the olefin-based rubbery polymer (a1) or crosslinked olefin-based rubbery polymer (a1), and prevents a decrease in the impact resistance of the resulting molded product. Examples of organic peroxides include cumene hydroperoxide, diisopropylbenzene hydroperoxide, and t-butyl hydroperoxide. As a redox initiator, a combination of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate, and dextrose or fructose is more preferred.

[0085] Examples of chain transfer agents include mercaptans (octyl mercaptan, n- or t-dodecyl mercaptan, n-hexadecyl mercaptan, n- or t-tetradecyl mercaptan, etc.), allyl compounds (allylsulfonic acid, metaallylsulfonic acid, sodium salts thereof, etc.), and α-methylstyrene dimers. Mercaptans are preferred as chain transfer agents because their molecular weight can be easily adjusted. One type of chain transfer agent may be used alone, or two or more types may be used in combination. The chain transfer agent may be added all at once, in installments, or continuously. The amount of chain transfer agent added is preferably 2.0 parts by mass or less per 100 parts by mass of monomer component (a2).

[0086] Examples of emulsifiers include anionic surfactants, nonionic surfactants, and amphoteric surfactants. Examples of anionic surfactants include sulfate esters of higher alcohols, alkylbenzene sulfonates, fatty acid sulfonates, phosphate salts, fatty acid salts, and amino acid derivative salts. Examples of nonionic surfactants include alkyl esters, alkyl ethers, and alkylphenyl ethers of ordinary polyethylene glycol. Examples of amphoteric surfactants include those having carboxylate salts, sulfate esters, sulfonates, or phosphate esters in the anionic part and amine salts, quaternary ammonium salts, or the like in the cationic part.

[0087] The amount of emulsifier added is preferably 10 parts by mass or less per 100 parts by mass of monomer component (a2).

[0088] The graft copolymer (A) obtained by emulsion polymerization is dispersed in an aqueous medium. A method for recovering the graft copolymer (A) from an aqueous dispersion containing the graft copolymer (A) is, for example, a precipitation method in which a precipitating agent is added to the aqueous dispersion, heated and stirred, the precipitating agent is separated, and the precipitated graft copolymer (A) is washed with water, dehydrated, and dried. Examples of precipitating agents include aqueous solutions of sulfuric acid, acetic acid, calcium chloride, and magnesium sulfate. One type of precipitating agent may be used alone, or two or more types may be used in combination. An antioxidant may be added to the aqueous dispersion containing the graft copolymer (A) as needed.

[0089] <Grafting Rate> The grafting rate of the graft copolymer (A) of the present invention is preferably 10 to 100% by mass, more preferably 20 to 60% by mass, and even more preferably 25 to 50% by mass, from the viewpoint of compatibility with other thermoplastic resins (B) described later. The specific method for measuring the grafting rate of the graft copolymer (A) is as shown in the Examples section below.

[0090] <Nitrogen Element Content> The nitrogen element content in 100% by mass of the graft copolymer (A) of the present invention is greater than 0% by mass and less than or equal to 1.5% by mass. From the viewpoint of compatibility with other thermoplastic resins (B) and the resulting improvement of various properties, this nitrogen element content is preferably 1.3% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.7% by mass or less. There is no particular lower limit to the nitrogen element content, but from the viewpoint of productivity (mechanical stability) during manufacturing and quality stability, it is more than 0% by mass, preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more.

[0091] By ensuring that the nitrogen element content is within the above range, productivity and quality stability during manufacturing are maintained, and furthermore, compatibility with other thermoplastic resins (B) described later is improved, resulting in a superior appearance of the resulting molded product. Due to this stability and compatibility, it is possible to achieve the high heat resistance that is the objective of the present invention, as well as to achieve a squeaking noise suppression effect and radio wave characteristics in the resulting molded product. In addition, if the nitrogen element content of the graft copolymer (A) is within the above range, good compatibility with other thermoplastic resins (B) described later is achieved, resulting in no delamination at the tensile fracture surface, and good appearance and impact resistance of the resulting thermoplastic resin composition and molded product. The specific method for measuring the nitrogen element content of the graft copolymer (A) is as shown in the Examples section below.

[0092] The nitrogen element content in 100% by mass of the graft copolymer (A) of the present invention is preferably attributable to the monomer component (a2) used in the production of the graft copolymer (A), and more preferably attributable to a vinyl cyanide monomer.

[0093] <Content of vinyl cyanide monomers> The content of vinyl cyanide monomers in the graft copolymer (A) of the present invention, that is, in the total 100% by mass of the olefin-based rubbery polymer (a1) and monomer component (a2), is preferably greater than 0% by mass and 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2% by mass or less. There is no particular lower limit to the content of vinyl cyanide monomers, but from the viewpoint of fully obtaining the effects of the present invention described above by using vinyl cyanide monomers, it is preferable that it is greater than 0% by mass and 0.05% by mass or more, particularly preferably 0.10% by mass or more, and especially preferably 0.50% by mass or more.

[0094] Here, the content of vinyl cyanide monomers in the graft copolymer (A) of the present invention corresponds to the ratio of vinyl cyanide monomers in monomer component (a2) to the total of olefin-based rubbery polymer (a1) and monomer component (a2).

[0095] <Number-average molecular weight (Mn) of acetone-soluble component> The number-average molecular weight (Mn) of the acetone-soluble component of the graft copolymer (A) of the present invention, measured using GPC, is preferably 10,000 to 100,000, more preferably 12,000 to 80,000, even more preferably 14,000 to 60,000, and particularly preferably 15,000 to 40,000. If the number-average molecular weight (Mn) of the acetone-soluble component of the graft copolymer (A) is within the above range, the compatibility with other thermoplastic resins (B) described later will be good, there will be no problems such as peeling, and the appearance and impact resistance of the resulting thermoplastic resin composition and molded article will be good. The specific method for measuring the number-average molecular weight (Mn) of the acetone-soluble component of the graft copolymer (A) is as shown in the Examples section below.

[0096] <Mass-average molecular weight (Mw) of acetone-soluble component> The mass-average molecular weight (Mw) of the acetone-soluble component of the graft copolymer (A) of the present invention, measured using GPC, is preferably 12,000 to 400,000, more preferably 17,000 to 280,000, even more preferably 22,000 to 180,000, and most preferably 27,000 to 100,000. If the mass-average molecular weight (Mw) of the acetone-soluble component of the graft copolymer (A) is within the above range, the compatibility with other thermoplastic resins (B) described later will be good, there will be no problems such as peeling, the resulting thermoplastic resin composition will have excellent fluidity and impact resistance, and the molded product will have a good appearance. The specific method for measuring the mass-average molecular weight (Mw) of the acetone-soluble component of the graft copolymer (A) is as described in the Examples section below.

[0097] <Molecular weight distribution (Mw / Mn) of acetone-soluble components> The molecular weight distribution (Mw / Mn) of the acetone-soluble components of the graft copolymer (A) of the present invention is 1.2 to 4.0, more preferably 1.4 to 3.5, even more preferably 1.6 to 3.0, and particularly preferably 1.8 to 2.5. When the molecular weight distribution (Mw / Mn) of the acetone-soluble components of the graft copolymer (A) is within the above range, the resulting thermoplastic resin composition tends to have better fluidity and impact resistance. The molecular weight distribution (Mw / Mn) of the acetone-soluble components of the graft copolymer (A) is calculated from the measured values ​​of the number-average molecular weight (Mn) and mass-average molecular weight (Mw) as described above.

[0098] [Thermoplastic Resin Composition] The thermoplastic resin composition of the present invention is a thermoplastic resin composition comprising the graft copolymer (A) of the present invention and other thermoplastic resins (B) other than the graft copolymer (A) (hereinafter simply referred to as "thermoplastic resin (B)").

[0099] <Thermoplastic Resin (B)> The graft copolymer (A) of the present invention exhibits excellent compatibility with thermoplastic resin (B). By blending the graft copolymer (A) of the present invention with thermoplastic resin (B), effects such as improved impact resistance, reduced specific gravity, suppression of squeaking noise in the resulting molded product, and improved radio wave characteristics are achieved. Furthermore, by blending the graft copolymer (A) of the present invention with thermoplastic resin (B), the effect of flame retardancy achieved by blending flame retardants such as phosphorus compounds and halogen compounds is enhanced, and the deterioration of electrical properties can be suppressed by reducing the amount of flame retardant used. As a result, a thermoplastic resin composition with a good balance of impact resistance, flame retardancy, and electrical properties, as well as good heat resistance, can be obtained. Moreover, in all cases, it can be expected that the deterioration of physical properties and surface appearance in high-temperature environments will be suppressed.

[0100] The thermoplastic resin composition of the present invention preferably contains 1 to 50 parts by mass of graft copolymer (A) and 50 to 99 parts by mass of thermoplastic resin (B) (provided that the total of graft copolymer (A) and thermoplastic resin (B) is 100 parts by mass). More preferably, the blending ratio is 5 to 50 parts by mass of graft copolymer (A) and 50 to 95 parts by mass of thermoplastic resin (B), even more preferably 10 to 45 parts by mass of graft copolymer (A) and 55 to 90 parts by mass of thermoplastic resin (B), and particularly preferably 15 to 40 parts by mass of graft copolymer (A) and 60 to 85 parts by mass of thermoplastic resin (B). The blending ratio of graft copolymer (A) and thermoplastic resin (B) in the thermoplastic resin composition of the present invention can be appropriately adjusted within the above preferred range according to the required properties.

[0101] Examples of thermoplastic resins (B) constituting the thermoplastic resin composition of the present invention include polyphenylene ether resins, polystyrene resins, polycarbonate resins, polyacrylic resins, polyamide resins, polyester resins, AS resins, ABS resins, ASA resins, AES resins, styrene-based thermoplastic elastomers, hydrogenated styrene-based thermoplastic elastomers, polyvinyl chloride resins, ethylene-vinyl acetate copolymers, polyarylates, fluorine-based resins, polyacetal resins, polypropylene resins, and polyphenylene sulfide. The thermoplastic resin composition of the present invention may contain one or more of these thermoplastic resins as thermoplastic resin (B).

[0102] Of these, the thermoplastic resin (B) according to the present invention is preferably polyphenylene ether resin, polystyrene resin, polycarbonate resin, polyacrylic resin, polyamide resin, or polyester resin, from the viewpoint of compatibility with the graft copolymer (A), appearance, and creaking noise resistance as a molded product, with polyphenylene ether resin, polystyrene resin, or polycarbonate resin being particularly preferred.

[0103] <Polyphenylene ether resin (PPE)> Polyphenylene ether resin is a polymer having a structural unit represented by the following formula as its main chain, and may be either a homopolymer or a copolymer.

[0104]

[0105] (wherein the two R ａ each independently represent a hydrogen atom, a halogen atom, a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a haloalkyl group, a hydrocarbonoxy group, or a halohydrocarbonoxy group. The two R ｂ each independently represent a hydrogen atom, a halogen atom, a primary or secondary alkyl group, an aryl group, a haloalkyl group, a hydrocarbonoxy group, or a halohydrocarbonoxy group, provided that the two R ａ do not both represent hydrogen atoms.)

[0106] As R ａ and R ｂ , a hydrogen atom, a primary or secondary alkyl group, and an aryl group are preferred. Preferable examples of primary alkyl groups include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-amyl group, an isoamyl group, a 2-methylbutyl group, a 2,3-dimethylbutyl group, a 2-, 3- or 4-methylpentyl group, and a heptyl group. Preferable examples of secondary alkyl groups include an isopropyl group, a sec-butyl group, and a 1-ethylpropyl group. In particular, R ａ is preferably a primary or secondary alkyl group having 1 to 4 carbon atoms or a phenyl group. R ｂ is preferably a hydrogen atom.

[0107] Suitable homopolymers of polyphenylene ether resins include, for example, polymers of 2,6-dialkylphenylene ethers such as poly(2,6-dimethyl-1,4-phenylene ether), poly(2,6-diethyl-1,4-phenylene ether), poly(2,6-dipropyl-1,4-phenylene ether), poly(2-ethyl-6-methyl-1,4-phenylene ether), and poly(2-methyl-6-propyl-1,4-phenylene ether). Suitable copolymers of polyphenylene ether resins include 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymers, 2,6-dimethylphenol / 2,3,6-triethylphenol copolymers, 2,6-diethylphenol / 2,3,6-trimethylphenol copolymers, 2,6-dipropylphenol / 2,3,6-trimethylphenol copolymers, and other 2,6-dialkylphenol / 2,3,6-trialkylphenol copolymers, as well as graft copolymers obtained by graft polymerization of styrene onto poly(2,6-dimethyl-1,4-phenylene ether), and graft copolymers obtained by graft polymerization of styrene onto 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymers.

[0108] In the present invention, poly(2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol / 2,3,6-trimethylphenol random copolymer is particularly preferred as the polyphenylene ether resin.

[0109] As the polyphenylene ether resin, a modified polyphenylene ether resin (m-PPE) can also be used, which is obtained by modifying (alloying) the above-mentioned polyphenylene ether resin with polystyrene resin, high-impact polystyrene, polycarbonate resin, or polyacrylic resin (hereinafter referred to as "alloyed resin") as described later. In this case, it is preferable that the blending ratio of the polyphenylene ether resin in the total of 100 parts by mass of the graft copolymer (A) and the modified polyphenylene ether resin (total of polyphenylene ether resin and alloyed resin) is 50 to 99 parts by mass, particularly 60 to 95 parts by mass, and especially 70 to 90 parts by mass. However, this blending ratio can be appropriately adjusted according to the required characteristics.

[0110] These polyphenylene ether resins may be used individually or in mixtures of two or more types.

[0111] <Polystyrene Resins (PS)> Polystyrene resins include general-purpose polystyrene (GPPS) and high-impact polystyrene (HIPS).

[0112] These polystyrene resins can be purchased and used commercially. Specifically, examples include CR-2500, CR-3500, and CR-2600 from DIC Corporation, HF77 and 697 from PS Japan Co., Ltd., and G100C, G200C, and G210C from Toyo Styrene Co., Ltd.

[0113] These polystyrene resins may be used individually or in mixtures of two or more types.

[0114] By incorporating impact-resistant polystyrene, among other polystyrene resins, compatibility with the graft copolymer (A) is improved, resulting in a thermoplastic resin composition with good impact resistance and surface appearance. Furthermore, squeaking noises in the resulting molded products can be effectively suppressed. In particular, the effect of suppressing deterioration of physical properties and surface appearance under high-temperature environments is obtained.

[0115] When a polystyrene resin is blended with a polyphenylene ether resin as a thermoplastic resin (B) in a graft copolymer (A), or when a polyphenylene ether resin modified (alloyed) with a polystyrene resin is blended, the blending ratio of the polystyrene resin is preferably 30 parts by mass or less, particularly 2 to 28 parts by mass, and especially 4 to 26 parts by mass, per 100 parts by mass of the total of the graft copolymer (A), polyphenylene ether resin, and polystyrene resin. This is preferable from the viewpoint of fluidity and heat resistance. However, this blending ratio can be appropriately adjusted according to the required properties.

[0116] <Polycarbonate Resin (PC)> Polycarbonate resins (preferably aromatic polycarbonate resins) can be any known polymerization method, such as those obtained by interfacial polycondensation between a dihydroxyaryl compound and phosgene, or by transesterification (melt polycondensation) between a dihydroxyaryl compound and a carbonate compound such as diphenyl carbonate.

[0117] Examples of the above-mentioned dihydroxyaryl compounds include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxyphenyl ether, 4,4'-dihydroxyphenyl sulfide, 4,4'-dihydroxyphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, hydroquinone, resorcinol, and the like. Furthermore, there are polyorganosiloxanes with hydroxyaryloxy-terminated structures (see, for example, U.S. Patent No. 3,419,634). These can be used individually or in combination of two or more. Among these, 2,2-bis(4-hydroxyphenylpropane (bisphenol A) is preferred.

[0118] The viscosity-average molecular weight (Mv) of the polycarbonate resin is preferably 12,000 to 40,000, more preferably 15,000 to 35,000, and particularly preferably 18,000 to 30,000. A higher molecular weight results in higher mechanical strength of the molded product, but tends to reduce fluidity and thus the appearance of the molded product. Two or more polycarbonate resins with different molecular weights can also be used. In this case, as long as the viscosity-average molecular weight of the polycarbonate resin mixture is within the above range, the viscosity-average molecular weight of each individual polycarbonate resin may be outside the above range.

[0119] Here, the viscosity-average molecular weight (Mv) of polycarbonate resins can usually be calculated by substituting the specific viscosity (ηsp), measured using methylene chloride as the solvent at 20°C and a concentration of (0.7 g / 100 mL - methylene chloride), into the following equation (2): Viscosity-average molecular weight = ([η] × 8130) １．２０５ …(2) Here, [η] = [(ηsp × 1.12 + 1) １／２ -1] / 0.56C. C represents the concentration.

[0120] <Polyacrylic resin (AR)> Polyacrylic resin is obtained by polymerizing a vinyl monomer containing a (meth)acrylic acid ester monomer or a mixture of this vinyl monomer by a known method. Here, "(meth)acrylic acid" means either or both of "acrylic acid" and "methacrylic acid". The vinyl monomer mixture has a (meth)acrylic acid ester monomer as an essential component and may optionally contain other vinyl monomers shown below in an amount of 40% by mass or less.

[0121] Examples of (meth)acrylic acid ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, and phenyl (meth)acrylate. These can be used individually or in combination of two or more.

[0122] Other vinyl monomers besides (meth)acrylic acid ester monomers include, for example, aromatic vinyl monomers, vinyl cyanide monomers, maleimide monomers, and (meth)acrylic acid, and can be used individually or in combination of two or more.

[0123] Examples of aromatic vinyl monomers and vinyl cyanide monomers include those exemplified as monomer component (a2) according to the present invention.

[0124] Examples of maleimide monomers include N-alkylmaleimides (N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-i-propylmaleimide, N-n-butylmaleimide, N-i-butylmaleimide, N-t-butylmaleimide, etc.), N-cycloalkylmaleimides (N-cyclohexylmaleimide, etc.), and N-arylmaleimides (N-phenylmaleimide, N-alkyl-substituted phenylmaleimide, N-chlorophenylmaleimide, etc.). These can be used individually or in combination of two or more.

[0125] Specific examples of copolymer resins of methyl methacrylate and methyl acrylate among polyacrylic resins include, for example, commercially available products such as "Parapet G (registered trademark)" from Kuraray Co., Ltd., and "Acrypet (registered trademark) VH" and "Acrypet (registered trademark) MD" from Mitsubishi Chemical Corporation. Specific examples of polyacrylic resins containing both (meth)acrylic acid ester monomer units and maleimide monomer units include, for example, commercially available products such as "Parapet SH-N" from Kuraray Co., Ltd. and "Polyimilex (registered trademark) PML203" from Nippon Shokubai Co., Ltd.

[0126] These polyacrylic resins may be used individually or in mixtures of two or more types.

[0127] <Polyamide resins (PA)> Examples of polyamide resins include polyamides obtained from diamines and dicarboxylic acids.

[0128] Examples of diamines include aliphatic, alicyclic, and aromatic diamines such as ethylenediamine, diaminobutane, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,3- and 1,4-bis(aminomethyl)cyclohexane, bis(p-aminocyclohexyl)methane, metaxylylenediamine, and paraxylylenediamine. These can be used individually or in combination of two or more.

[0129] Examples of dicarboxylic acids include aliphatic, alicyclic, and aromatic dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid. These can be used individually or in combination of two or more.

[0130] As the polyamide resin, for example, polyamides obtained by ring-opening polymerization of lactams such as ξ-caprolactam and ω-dodecalactam; polyamides obtained from 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, etc.; copolymerized polyamides of these; mixed polyamides of these; polyamide elastomers in which the polyamide is used as the hard segment and the polyether is used as the soft segment; and the like may be used.

[0131] Among these, polycaproamide (nylon 6), polyundecanamide (nylon 11), polydodecaamide (nylon 12), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebakamid (nylon 610), and copolymers thereof are preferred because they can be manufactured industrially at low cost and in large quantities. Examples of copolymers include nylon 6 / 66, nylon 6 / 610, nylon 6 / 12, nylon 66 / 12, and nylon 6 / 66 / 610 / 12. Polyamide resins may also be mixtures thereof. Bis(p-aminocyclohexyl)methane / terephthalic acid / isophthalic acid-based polyamides are also preferred as polyamide resins.

[0132] These polyamide resins may be used individually or as a mixture of two or more types.

[0133] <Polyester Resins> As polyester resins (preferably aromatic polyester resins), polymers or copolymers obtained by a polycondensation reaction mainly consisting of a dicarboxylic acid (or its ester-forming derivative) and a diol component can be used.

[0134] Examples of the above-mentioned dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, 2,5-anthracenedicarboxylic acid, 2,6-anthracenedicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid, and 2,5-pyridinedicarboxylic acid. Among these, terephthalic acid is preferred.

[0135] These dicarboxylic acid components may be used in combination of two or more types. In small amounts, these aromatic dicarboxylic acid components may be used in combination with one or more aliphatic dicarboxylic acid components such as adipic acid, azelaic acid, dodecanedionic acid, and sebacic acid, and alicyclic dicarboxylic acid components such as cyclohexanedicarboxylic acid.

[0136] Examples of diol components include aliphatic diols such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, diethylene glycol, and triethylene glycol, alicyclic diols such as 1,4-cyclohexanedimethanol, and mixtures thereof. Of these, ethylene glycol, propylene glycol, and butylene glycol are preferred. In small amounts, one or more long-chain diols with a molecular weight of 400 to 6,000, such as polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol, may be used in combination.

[0137] Preferred examples of these polymers or copolymers include polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polyethylene-1,2-bis(phenoxy)ethane-4,4'-dicarboxylate. Of these, PET and PBT are preferred from the viewpoint of ease of processing and mechanical properties.

[0138] These polyester resins may be used individually or as a mixture of two or more. For example, PET and PBT may be used as a mixture.

[0139] <Other Components> In addition to the graft copolymer (A) and thermoplastic resin (B), various additives may be added to the thermoplastic resin composition of the present invention to an extent that does not impair the effects of the present invention.

[0140] Various additives that can be incorporated into the thermoplastic resin composition of the present invention include: antioxidants such as hindered phenols, sulfur organic compounds, and phosphorus organic compounds; heat stabilizers such as phenols and acrylates; transesterification inhibitors such as mixtures of monostearyl acid phosphate and distearyl acid phosphate; ultraviolet absorbers such as benzotriazoles, benzophenones, and salicylates; various stabilizers such as organonickels and hindered amines; lubricants such as metal salts of higher fatty acids and higher fatty acid amides; plasticizers such as phthalates and phosphate esters; halogen-containing compounds such as polybromodiphenyl ethers, tetrabromobisphenol-A, brominated epoxy oligomers, and brominated polycarbonate oligomers; flame retardants and flame retardant aids such as phosphate ester flame retardants, phosphorus compounds (flame retardants), and antimony trioxide; carbon black, titanium dioxide, and other pigments and dyes.

[0141] <Content of olefin-based rubbery polymer (a1) in thermoplastic resin composition> The content of olefin-based rubbery polymer (a1) in the thermoplastic resin composition of the present invention is preferably 2 to 30% by mass, more preferably 4 to 25% by mass, even more preferably 5 to 20% by mass, and particularly preferably 6 to 18% by mass, based on 100% by mass of the thermoplastic resin composition. If the content of olefin-based rubbery polymer (a1) is within the above range, the resulting thermoplastic resin composition will have excellent fluidity and impact resistance, and furthermore, the molded product will have good heat resistance, noise resistance, and radio wave characteristics.

[0142] <Nitrogen Element Content> The nitrogen element content of the thermoplastic resin composition of the present invention is preferably greater than 0% by mass and 6.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 1.0% by mass or less, and particularly preferably 0.1% by mass or less, based on 100% by mass of the thermoplastic resin composition. On the other hand, there is no particular limit to the lower limit of this nitrogen element content, but from the viewpoint of confirming that the dispersibility of the graft copolymer (A) in the thermoplastic resin composition of the present invention is good, it is preferably greater than 0% by mass, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more. If the nitrogen element content of the thermoplastic resin composition is within the above range, the compatibility between the graft copolymer (A) and the thermoplastic resin (B) is good, the appearance of the resulting molded article is excellent, and it is possible to fully exhibit the fluidity and heat resistance that are the objectives of the present invention, as well as the squeaking noise suppression effect and radio wave characteristics of the molded article.

[0143] The specific method for measuring the nitrogen element content of the thermoplastic resin composition is as shown in the Examples section below.

[0144] The nitrogen content of the thermoplastic resin composition of the present invention is due to the components contained in the thermoplastic resin composition. In particular, it is preferable that the nitrogen content of the thermoplastic resin composition of the present invention is due to the vinyl cyanide monomers mentioned above, especially the vinyl cyanide monomer units contained in the graft copolymer (A) of the present invention in the thermoplastic resin composition.

[0145] <Content of vinyl cyanide monomers> The content of vinyl cyanide monomers in 100% by mass of the thermoplastic resin composition of the present invention is preferably greater than 0% by mass and 30% by mass or less, more preferably 15% by mass or less, even more preferably 5% by mass or less, and particularly preferably 0.5% by mass or less. There is no particular limit to the lower limit of this content, but from the viewpoint of confirming that the dispersibility of the graft copolymer (A) in the thermoplastic resin composition of the present invention is good, it is preferably greater than 0% by mass, 0.05% by mass or more, particularly 0.08% by mass or more, and especially 0.1% by mass or more.

[0146] Here, the content of vinyl cyanide monomers in the thermoplastic resin composition refers to the content of vinyl cyanide monomer units contained in the thermoplastic resin composition. The content of vinyl cyanide monomers in the thermoplastic resin composition corresponds to the sum of the content of vinyl cyanide monomer units contained in the graft copolymer (A) of the present invention and the content of vinyl cyanide monomer units contained in the thermoplastic resin (B). Therefore, the acrylonitrile content in the thermoplastic resin composition shown in Tables 2 to 5 below also corresponds to the content of acrylonitrile units in the thermoplastic resin composition, that is, the ratio of the total acrylonitrile units contained in the graft copolymer (A) and thermoplastic resin (B) to the thermoplastic resin composition.

[0147] [Molded Articles] Molded articles of the present invention are obtained by molding the thermoplastic resin composition of the present invention using known molding methods. Examples of molding methods for the thermoplastic resin composition of the present invention include injection molding, press molding, extrusion molding, vacuum molding, blow molding, and the like.

[0148] The molded articles produced by molding the thermoplastic resin composition of the present invention do not suffer from the aforementioned peeling problems, have excellent surface appearance (surface gloss), impact resistance, and heat resistance, and are low in specific gravity (lightweight). Furthermore, they also exhibit noise suppression and radio wave characteristics. For these reasons, the molded articles of the present invention can be effectively applied to a wide range of uses.

[0149] Applications of the molded articles of the present invention include automotive applications, mechanical components, electrical and electronic components, office automation equipment, office equipment, food containers, stationery, and general merchandise. Among these, the molded articles of the present invention are particularly suitable for use as automotive parts. Furthermore, due to their excellent dielectric properties in the high-frequency band, they are especially useful for high-speed communication equipment components.

[0150] Examples of mechanical components, electrical and electronic components, and automotive components to which the molded articles of the present invention are applied include industrial equipment such as office machines, measuring instruments, chassis, industrial robots, internal parts of electrical equipment, power adapters for home appliances, robotic vacuum cleaners and their charging docks, recording media and their drives, sensor devices, and terminal blocks. More specifically, concrete examples of mechanical components, electrical components, electronic components, and automotive components include circuit breakers, electromagnetic switches, focus cases, flyback transformers, molded parts for fusers in photocopiers and printers, housings for general household appliances and office automation equipment, variable capacitor case components, various end plates, transformers, printed circuit boards, housings, terminal blocks, coil bobbins, connectors, relays, disk drive chassis, transformers, switch components, outlet components, motor components, sockets, plugs, capacitors, various cases, resistors, electrical and electronic components incorporating metal terminals and wires, computer-related components, audio components such as acoustic components, lighting components, telegraph equipment-related components, telephone equipment-related components, air conditioner components, home appliance components such as VTRs and televisions, photocopier components, facsimile components, optical equipment components, automotive ignition system components, automotive connectors, and various automotive electrical components. Furthermore, the molded products of the present invention can also be used for aircraft components, drones, etc., due to their lightweight design. Furthermore, the molded articles of the present invention can also be used in electrical and electronic components used in secondary batteries, fuel cells, photovoltaic power generation (solar cells), solar thermal power generation, geothermal power generation, wind power generation, smart meters, etc. in the energy and environmental fields, as well as electrical components that make up power transmission equipment, cable terminals, and automotive parts. In particular, they are especially suitable as connectors for photovoltaic power generation modules, junction boxes for photovoltaic power generation modules and other connectors for photovoltaic power generation modules, and as parts for hybrid and electric vehicles.

[0151] The molded articles of the present invention, obtained by molding the thermoplastic resin composition of the present invention, are suitable for high-speed communication, high-frequency communication and electronic equipment components, and in-vehicle applications equipped with high-frequency communication and electronic equipment, due to their excellent radio wave characteristics in the high-frequency band. Specific examples of high-speed communication and high-frequency communication and electronic equipment components include 5G mobile communication terminals and communication base stations, quasi-millimeter wave sensors, millimeter wave sensors, in-vehicle communication equipment such as ETC, and their housings such as radomes, antenna covers, sensor covers, Bluetooth communication equipment, and wireless equipment used in drones, etc. They can also be used for antennas, connectors, switches, filters, converters, couplers, circulators, isolators, capacitors, inductors, coils, resonators, FPCs, etc. The molded articles of the present invention are also suitable for millimeter-wave radar components, millimeter-wave radar radomes, and millimeter-wave radars, and are also useful for these vehicle applications due to their excellent squeaking noise suppression effect. The molded articles made from the thermoplastic resin composition of the present invention can constitute a millimeter-wave radome themselves. Furthermore, the molded product of the present invention can be used as a millimeter-wave permeable resin component and combined with other resin components to construct a millimeter-wave radome.

[0152] The millimeter-wave radome using the molded product of the present invention suppresses creaking noise and provides a millimeter-wave radar with excellent radio wave characteristics, surface appearance, durability, and reliability.

[0153] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" in the following examples are based on mass.

[0154] [Examples and Comparative Examples of Graft Polymers] [Measurement and Evaluation Methods] The various measurement and evaluation methods in the following examples and comparative examples are as follows.

[0155] <Measurement of Average Particle Diameter> The volume-average particle diameter (MV) measured using Microtrac (Nanotrac 150, manufactured by Nikkiso Co., Ltd.) with pure water as the measurement solvent was defined as the average particle diameter. It has been confirmed by electron microscope image analysis that the average particle diameter of the olefin-based rubbery polymer (a1) dispersed in the aqueous dispersion and the crosslinked olefin-based rubbery polymer (a1) directly represents the average particle diameter of the olefin-based rubbery polymer (a1) and crosslinked olefin-based rubbery polymer (a1) in the thermoplastic resin composition.

[0156] <Measurement of graft rate and average molecular weight of acetone-soluble components> 1 g of graft copolymer (A) was added to 80 mL of acetone and heated under reflux for 3 hours. The resulting suspension of acetone solution was centrifuged at 14,000 rpm for 30 minutes using a centrifuge (Hitachi Koki Co., Ltd. "CR21E") to separate the precipitated component (acetone-insoluble component) from the acetone solution (acetone-soluble component).

[0157] Grafting rate calculation: The precipitated component (acetone-insoluble component) was dried and its mass (Y (g)) was measured, and the grafting rate was calculated from the following formula (3). In formula (3), Y is the mass (g) of the acetone-insoluble component of the graft copolymer (A). X is the total mass (g) of the graft copolymer (A) used to determine Y. The rubber fraction is the solid content ratio of the olefin-based rubbery polymer (a1) or crosslinked olefin-based rubbery polymer (a1) in the graft copolymer (A). Grafting rate (%) = {(Y - X × rubber fraction) / X × rubber fraction} × 100 …(3)

[0158] Measurement of the average molecular weight of acetone-soluble components: The acetone solution (acetone-soluble components) was filtered through a glass filter, and the resulting filtrate was concentrated to dryness using an evaporator. The remaining solid was dissolved in tetrahydrofuran, and the mass-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) in polystyrene equivalent were measured using GPC (GPC: Waters "GPC / V2000", column: Showa Denko "Shodex AT-G + AT-806MS").

[0159] <Evaluation of Mechanical Stability of Latex> The mechanical stability of graft-polymerized latex was evaluated using the SMT Corporation's Highflex Disperser "HG92". 300 mL of latex was placed in a 500 mL stainless steel container (80 mm in diameter x 120 mm in height), and a convection-type shaft (model PB-1, dimensions 40Φ) was attached to the apparatus. The height was adjusted so that the bottom of the shaft was 1 cm above the bottom of the container. The mixture was then stirred at 10,000 rpm, and the time during which the emulsion state of the latex was maintained (the time until the solidified or liquid state could no longer be maintained: a maximum of 900 seconds) was measured. When the polymerized latex is subjected to mechanical shear by a transfer pump, if some of the emulsion state is broken, aggregates (foreign matter) are generated. In particular, if the foreign matter is fine, it cannot be removed and proceeds to the solidification process, where the generated foreign matter mixes with the normal graft copolymer, degrading the quality of the product. Therefore, the mechanical stability of this latex is an important characteristic.

[0160] <Measurement of Nitrogen Content> The nitrogen element (N) present in the graft copolymer and thermoplastic resin composition was analyzed using the following elemental analyzer. If the element was not detected, it was indicated as "N.D.". Elemental analyzer: JM10 MICROCORDER (manufactured by J-SCIENCE-LAB Co., Ltd.)

[0161] <<Graft Copolymer (A)>> [Production Example 1: Olefin-based Rubber-like Polymer (a1)] <Preparation of Aqueous Dispersion of Olefin-based Rubber-like Polymer (a1)> 100 parts of EPDM (Tafmer TP3180, manufactured by Mitsui Chemicals, Inc.), 12 parts of low molecular weight modified polyethylene (Highwax 2203A, manufactured by Mitsui Chemicals, Inc., mass average molecular weight: 2700, acid value: 30 mg-KOH / g), and 2.4 parts of semi-hardened beef tallow fatty acid potassium soap (KS Soap, manufactured by Kao Corporation) were mixed. Next, these mixtures were continuously supplied from the hopper of a twin-screw extruder (PCM-30, manufactured by Ikegai Co., Ltd.), and while continuously supplying a 14% aqueous potassium hydroxide solution, the mixture was melted and kneaded at a heating temperature of 200°C and the molten material was extruded. Subsequently, the molten material was continuously supplied to a single-screw extruder for cooling attached to the tip of the extruder and cooled to 90°C. The extracted solid was placed in 80°C hot water and continuously dispersed to obtain an aqueous dispersion of an olefin-based rubbery polymer (a1) with an average particle size of 0.45 μm.

[0162] <Crosslinking treatment of olefin-based rubbery polymer (a1)> An aqueous dispersion of the above olefin-based rubbery polymer (a1) (100 parts in terms of solid content) was placed in a reaction vessel equipped with a stirrer, distilled water was added to bring the solid content concentration to 35%, 1.0 part of t-butyl hydroperoxide as an organic peroxide and 1.0 part of divinylbenzene as a polyfunctional compound were added, and the mixture was reacted at 130°C for 5 hours to prepare a crosslinked olefin-based rubbery polymer (a1) with a gel content of 60% by mass and an average particle size of 0.45 μm.

[0163] [Example I-1: Graft Copolymer (A-1)] In a reaction vessel equipped with a stirrer, 70 parts of crosslinked olefin-based rubbery polymer (a1) (based on solid content) and 1.5 parts of KS soap were placed. Distilled water was added to bring the solid content concentration to 30%, and 0.007 parts of ferrous sulfate, 0.3 parts of tetrasodium pyrophosphate, and 0.37 parts of fructose were added, and the temperature of the contents was set to 80°C. 29.25 parts of styrene and 0.75 parts of acrylonitrile as monomer components (a2), 0.6 parts of cumene hydroperoxide, 1.0 part of KS soap, and 0.14 parts of potassium hydroxide were continuously supplied for 210 minutes, maintaining the temperature of the contents at 80°C, and the graft polymerization reaction was carried out by emulsion polymerization. After polymerization, an antioxidant was added to the aqueous dispersion containing the graft copolymer, and the latex of this graft copolymer was pumped through piping to the next solidification step (solidification tank). In a coagulation tank, solid components were precipitated with sulfuric acid, and then, after washing, dehydration, and drying, a powdery graft copolymer (A-1) was obtained. The grafting rate of the graft copolymer (A-1) was 41.4%, the mass-average molecular weight (Mw) of the acetone-soluble component was 37,000, the number-average molecular weight (Mn) was 19,000, and the molecular weight distribution (Mw / Mn) was 1.95.

[0164] [Example I-2: Graft Copolymer (A-2)] Graft copolymer (A-2) was obtained in the same manner as graft copolymer (A-1), except that the monomer component (a2) was 28.5 parts styrene and 1.5 parts acrylonitrile in the graft polymerization reaction. The grafting rate of graft copolymer (A-2) was 41.1%, the mass-average molecular weight (Mw) of the acetone-soluble component was 36,200, the number-average molecular weight (Mn) was 18,500, and the molecular weight distribution (Mw / Mn) was 1.96.

[0165] [Example I-3: Graft Copolymer (A-3)] Graft copolymer (A-3) was obtained in the same manner as graft copolymer (A-1), except that the monomer component (a2) was 27.0 parts styrene and 3.0 parts acrylonitrile in the graft polymerization reaction. The grafting rate of graft copolymer (A-3) was 40.8%, the mass-average molecular weight (Mw) of the acetone-soluble component was 35,000, the number-average molecular weight (Mn) was 18,000, and the molecular weight distribution (Mw / Mn) was 1.94.

[0166] [Example I-4: Graft Copolymer (A-4)] In a reaction vessel equipped with a stirrer, 60 parts of crosslinked olefin-based rubbery polymer (a1) (in terms of solid content) and 1.5 parts of KS soap were added. Distilled water was added to bring the solid content concentration to 30%, and 0.007 parts of ferrous sulfate, 0.3 parts of tetrasodium pyrophosphate, and 0.37 parts of fructose were added, and the temperature of the contents was set to 80°C. 39.0 parts of styrene and 1.0 part of acrylonitrile as monomer components (a2), 0.6 parts of cumene hydroperoxide, 1.0 part of KS soap, and 0.14 parts of potassium hydroxide were continuously supplied for 210 minutes, maintaining the temperature of the contents at 80°C, and the graft polymerization reaction was carried out by emulsion polymerization. After polymerization, an antioxidant was added to the aqueous dispersion containing the graft copolymer, and the latex of this graft copolymer was pumped through piping to the next solidification step (solidification tank). In a coagulation tank, solid components were precipitated with sulfuric acid, and after washing, dehydration, and drying, a powdery graft copolymer (A-4) was obtained. The grafting rate of the graft copolymer (A-4) was 63.4%, the mass-average molecular weight (Mw) of the acetone-soluble component was 36,000, the number-average molecular weight (Mn) was 22,000, and the molecular weight distribution (Mw / Mn) was 1.64.

[0167] [Example I-5: Graft Copolymer (A-5)] Graft copolymer (A-5) was obtained in the same manner as graft copolymer (A-4), except that the monomer component (a2) was 38.0 parts styrene and 2.0 parts acrylonitrile in the graft polymerization reaction. The grafting rate of graft copolymer (A-5) was 63.1%, the mass-average molecular weight (Mw) of the acetone-soluble component was 35,500, the number-average molecular weight (Mn) was 21,800, and the molecular weight distribution (Mw / Mn) was 1.63.

[0168] [Example I-6: Graft Copolymer (A-6)] Graft copolymer (A-6) was obtained in the same manner as graft copolymer (A-4), except that the monomer component (a2) was 36.0 parts styrene and 4.0 parts acrylonitrile in the graft polymerization reaction. The grafting rate of graft copolymer (A-6) was 62.5%, the mass-average molecular weight (Mw) of the acetone-soluble component was 34,800, the number-average molecular weight (Mn) was 21,200, and the molecular weight distribution (Mw / Mn) was 1.64.

[0169] [Example I-7: Graft Copolymer (A-7)] In a reaction vessel equipped with a stirrer, 50 parts of crosslinked olefin-based rubbery polymer (a1) (in terms of solid content) and 1.5 parts of KS soap were added. Distilled water was added to bring the solid content concentration to 30%, and 0.007 parts of ferrous sulfate, 0.3 parts of tetrasodium pyrophosphate, and 0.37 parts of fructose were added, and the temperature of the contents was set to 80°C. 48.75 parts of styrene and 1.25 parts of acrylonitrile as monomer components (a2), 0.6 parts of cumene hydroperoxide, 1.0 part of KS soap, and 0.14 parts of potassium hydroxide were continuously supplied for 210 minutes, maintaining the temperature of the contents at 80°C, and the graft polymerization reaction was carried out by emulsion polymerization. After polymerization, an antioxidant was added to the aqueous dispersion containing the graft copolymer, and the latex of this graft copolymer was pumped through piping to the next solidification step (solidification tank). In a coagulation tank, solid components were precipitated with sulfuric acid, and after washing, dehydration, and drying, a powdery graft copolymer (A-4) was obtained. The grafting rate of the graft copolymer (A-7) was 78.9%, the mass-average molecular weight (Mw) of the acetone-soluble component was 29,800, the number-average molecular weight (Mn) was 18,000, and the molecular weight distribution (Mw / Mn) was 1.66.

[0170] [Example I-8: Graft Copolymer (A-8)] Graft copolymer (A-8) was obtained in the same manner as graft copolymer (A-7), except that the monomer component (a2) was 47.5 parts styrene and 2.5 parts acrylonitrile in the graft polymerization reaction. The grafting rate of graft copolymer (A-8) was 79.5%, the mass-average molecular weight (Mw) of the acetone-soluble component was 29,600, the number-average molecular weight (Mn) was 17,600, and the molecular weight distribution (Mw / Mn) was 1.68.

[0171] [Example I-9: Graft Copolymer (A-9)] Graft copolymer (A-9) was obtained in the same manner as graft copolymer (A-7), except that the monomer component (a2) was 45.0 parts styrene and 5.0 parts acrylonitrile in the graft polymerization reaction. The grafting rate of graft copolymer (A-9) was 80.5%, the mass-average molecular weight (Mw) of the acetone-soluble component was 29,100, the number-average molecular weight (Mn) was 17,200, and the molecular weight distribution (Mw / Mn) was 1.69.

[0172] [Comparative Example I-1: Graft Copolymer (A'-10)] In a reaction vessel equipped with a stirrer, 50 parts of crosslinked olefin-based rubbery polymer (a1) (in terms of solid content) and 1.5 parts of KS soap were placed, distilled water was added to bring the solid content concentration to 30%, 0.007 parts of ferrous sulfate, 0.3 parts of tetrasodium pyrophosphate, and 0.37 parts of fructose were added, and the temperature of the contents was set to 80°C. 50 parts of styrene and 0.6 parts of cumene hydroperoxide, along with 1.1 parts of KS soap and 0.14 parts of potassium hydroxide were continuously supplied for 210 minutes, maintaining the temperature of the contents at 80°C, and emulsion polymerization was carried out. After polymerization, an antioxidant was added to the aqueous dispersion containing the graft copolymer, and the latex of this graft copolymer was pumped through piping to the next solidification step (solidification tank). In the solidification tank, the solid content was precipitated with sulfuric acid, and after washing, dewatering, and drying steps, powdered graft copolymer (A'-10) was obtained. The grafting rate of the graft copolymer (A'-10) was 80.1%, the mass-average molecular weight (Mw) of the acetone-soluble component was 28,800, the number-average molecular weight (Mn) was 17,600, and the molecular weight distribution (Mw / Mn) was 1.64.

[0173] [Comparative Example I-2: Graft Copolymer (A'-11)] In a reaction vessel equipped with a stirrer, 60 parts of crosslinked olefin-based rubbery polymer (a1) (in terms of solid content) and 1.5 parts of KS soap were placed, distilled water was added to bring the solid content concentration to 30%, 0.007 parts of ferrous sulfate, 0.3 parts of tetrasodium pyrophosphate, and 0.37 parts of fructose were added, and the temperature of the contents was set to 80°C. 30 parts of styrene, 10 parts of acrylonitrile, and 0.6 parts of cumene hydroperoxide, along with 1.0 part of KS soap and 0.14 parts of potassium hydroxide were continuously supplied for 210 minutes, maintaining the temperature of the contents at 80°C, and emulsion polymerization was carried out. After polymerization, an antioxidant was added to the aqueous dispersion containing the graft copolymer, and the latex of this graft copolymer was pumped through piping to the next solidification step (solidification tank). In a coagulation tank, solid components were precipitated with sulfuric acid, and after washing, dehydration, and drying, a powdery graft copolymer (A'-11) was obtained. The grafting rate of the graft copolymer (A'-11) was 62.1%, the mass-average molecular weight (Mw) of the acetone-soluble component was 47,000, the number-average molecular weight (Mn) was 29,000, and the molecular weight distribution (Mw / Mn) was 1.62.

[0174] [Comparative Example I-3: Graft Copolymer (A'-12)] In a reaction vessel equipped with a stirrer, 60 parts of polybutadiene latex with a volume-average particle size of 0.34 μm (based on solid content) and 1.5 parts of KS soap were placed. Distilled water was added to bring the solid content concentration to 30%, and 0.007 parts of ferrous sulfate, 0.3 parts of tetrasodium pyrophosphate, and 0.37 parts of fructose were added to bring the temperature of the contents to 65°C. 30 parts of styrene, 10 parts of acrylonitrile, and 0.6 parts of cumene hydroperoxide, along with 1.0 part of KS soap and 0.14 parts of potassium hydroxide, were continuously supplied for 210 minutes, maintaining the temperature of the contents at 80°C, and emulsion polymerization was carried out. After polymerization, an antioxidant was added to the aqueous dispersion containing the graft copolymer, and the graft copolymer latex was pumped through piping to the next solidification step (solidification tank). In a coagulation tank, solid components were precipitated with sulfuric acid, and after washing, dehydration, and drying, a powdery graft copolymer (A'-12) was obtained. The grafting rate of the graft copolymer (A'-12) was 45.0%, the mass-average molecular weight (Mw) of the acetone-soluble component was 48,100, the number-average molecular weight (Mn) was 16,500, and the molecular weight distribution (Mw / Mn) was 2.91.

[0175] Table 1 shows the evaluation results of the graft copolymers obtained in Examples I-1 to 9 and Comparative Examples I-1 to 3.

[0176]

[0177] Table 1 shows that the graft copolymers (A-1) to (A-9) of the present invention have excellent latex mechanical stability because their nitrogen element content meets the range of the present invention. In contrast, the graft copolymer (A'-10) that does not contain nitrogen element has extremely low latex mechanical stability. Graft copolymers (A'-11) and (A'-12) have excellent latex mechanical stability, but as described later, they do not have compatibility when mixed with thermoplastic resin (B) and are therefore unusable.

[0178] [Examples, Comparative Examples, and Reference Examples of Thermoplastic Resin Compositions] [Examples II-1 to 15, Comparative Examples II-1 to 5, Reference Examples] <Production of Thermoplastic Resin Compositions> The graft copolymer (A) or (A') shown in Tables 2 to 5 and the thermoplastic resin (B) shown below were mixed in the proportions shown in Tables 2 to 5. Then, using a twin-screw extruder (manufactured by Japan Steel Works, model name "TEX44"), the mixture was melt-kneaded at the molding temperature (cylinder temperature) shown in Tables 2 to 5 and a screw rotation speed of 250 rpm to form pellets. The obtained thermoplastic resin composition was used for the following measurements, the preparation and evaluation of evaluation test pieces by injection molding, and the evaluation of radio wave properties. The results are shown in Tables 2 to 5. In Tables 2 to 5, the acrylonitrile content in the thermoplastic resin composition is a value calculated from the content ratio of acrylonitrile units contained in the graft copolymer (A) or graft copolymer (A') used and the content ratio of graft copolymer (A) or graft copolymer (A') in the thermoplastic resin composition.

[0179] <Thermoplastic Resins (B)> (B-1): Polyphenylene ether resin PPE: Yupiace® PX-100F manufactured by Global Polyacetal Co., Ltd. (Poly(2,6-dimethyl-1,4-phenylene ether) resin) (B-2): Polystyrene resin GPPS: G100C manufactured by Toyo Styrene Co., Ltd. (B-3): Polycarbonate resin PC: Yupiron® S-3000, Mv: 22,000 manufactured by Mitsubishi Engineering Plastics Co., Ltd. (B-4): Modified polyphenylene ether resin m-PPE: Yupiace® AH91 manufactured by Global Polyacetal Co., Ltd. (Polystyrene resin modified polyphenylene ether resin)

[0180] [Measurement and Evaluation Methods] The various measurement and evaluation methods in the following examples and comparative examples are as follows.

[0181] <Evaluation of fluidity: Melt volume rate (MVR)> Using pellets of the obtained thermoplastic resin composition, the melt volume flow rate was measured in accordance with ISO 1133 under conditions of 270°C and a 10 kg load. However, the measurement was performed at 220°C for Example II-13 and 240°C for Example II-14. The MVR of the thermoplastic resin composition is an indicator of the appropriate temperature and flow characteristics for molding, and from the viewpoint of obtaining a good molded product, it was set to 5-30 cm. ３ It is preferable that the range is / 10min.

[0182] <Preparation of Test Specimen (a)> The obtained thermoplastic resin composition pellets were injection molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., product name "IS55FP-1.5A") under conditions of cylinder temperature of 220 to 300°C and mold temperature of 60°C to obtain a test specimen (a) measuring 80 mm in length, 10 mm in width, and 4 mm in thickness. However, Example II-13 was molded at a cylinder temperature of 180 to 220°C, and Example II-14 was molded at a cylinder temperature of 220 to 260°C. This test specimen (a) was used to measure Charpy impact strength, temperature of deflection under load, flexural modulus, and specific gravity.

[0183] <Evaluation of impact resistance: Charpy impact test (C-IMP)> Using test specimen (a), a Charpy impact test (with notch) was performed at 23°C in accordance with ISO 179 standards, and the Charpy impact strength was measured.

[0184] <Heat resistance evaluation: Temperature of deflection under load (HDT)> Using test specimen (a), the temperature of deflection under load was measured by the flatwise method in accordance with ISO 75 standards. The load was set to 1.80 MPa.

[0185] <Evaluation of flexural modulus> Using test specimen (a), the flexural modulus was measured at a temperature of 23°C in accordance with the ISO 178 standard.

[0186] <Measurement of Density (Specific Gravity)> The density was measured using test specimen (a) in accordance with ISO 1183 standard.

[0187] <Preparation of Test Specimen (b)> A dumbbell-shaped tensile test specimen (b) with a total length of 170 mm, a parallel section length of 80 mm, a central parallel section width of 10 mm, and a thickness of 4 mm was obtained by injection molding a pellet of thermoplastic resin composition using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., product name "IS55FP-1.5A") under the conditions of a cylinder temperature of 220 to 300°C and a mold temperature of 60°C. However, in Example II-13, the cylinder temperature was 180 to 220°C, and in Example II-14, it was 220 to 260°C. This test specimen (b) was used for the observation of the tensile fracture surface described below.

[0188] <Observation of Tensile Fracture Surface> Using specimen (b), the tensile fracture surface was observed in accordance with the ISO 527 standard. If there was no delamination of the resin layer on the fracture surface, it was marked with "○". If there was very slight delamination, it was marked with "△". If there was significant delamination, it was marked with "×".

[0189] <Preparation of Test Specimen (c)> Pellets of the thermoplastic resin composition were injection molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., product name "IS55FP-1.5A") with a flat plate mold (single-point pin gate) at a cylinder temperature of 220 to 300°C and a mold temperature of 60°C to obtain a test specimen (c) measuring 100 mm in length, 100 mm in width, and 2 mm in thickness. However, Example II-13 was molded at a cylinder temperature of 180 to 220°C, and Example II-14 was molded at a cylinder temperature of 220 to 260°C. This test specimen (c) was used to evaluate the surface appearance (surface gloss, clarity).

[0190] <Evaluation of Surface Gloss> A digital angle-bending gloss meter (UGV-5D, manufactured by Suga Test Instruments Co., Ltd.) was used to measure the gloss value of the central part of test piece (c) at incident angles of 60° and 20°. A higher measured value at either angle indicates better gloss.

[0191] <Evaluation of Image Clarity> The image clarity of test piece (c) was measured using an image clarity measuring device (Suga Test Instruments Co., Ltd., ICM-1DP type image clarity measuring device, slit spacing 1 mm, reflection angle 60°). A higher measured value indicates better image clarity. The evaluation of image clarity allows for comparison of the degree of image reflection depending on the surface condition (scratches, foreign matter, etc.). For this reason, image clarity is more effective than surface gloss value for evaluating the surface condition.

[0192] <Evaluation of creaking noise after thermal degradation (measurement of abnormal noise risk index)> A molded product measuring 150 mm in length, 100 mm in width, and 4 mm in thickness was obtained by injection molding a pellet of thermoplastic resin composition using an injection molding machine (Toshiba Machine product name "IS-170FA") under the conditions of cylinder temperature 250°C, injection pressure 50 MPa, and mold temperature 60°C. From this molded product, test pieces measuring 60 mm in length, 100 mm in width, and 4 mm in thickness, and 50 mm in length, 25 mm in width, and 4 mm in thickness were cut out using a disc saw. Next, the edges of the test pieces were chamfered with #100 grit sandpaper, and then fine burrs were removed with a utility knife to obtain two test pieces of different sizes for evaluating creaking noise. The two test pieces for evaluating creaking noise were left in an oven chamber adjusted to 80°C ± 5°C for 300 hours, and then cooled at 25°C for 24 hours to obtain evaluation test pieces that had been thermally aged. Two heat-aged test pieces of different sizes were placed in a Ziegler SSP-02 stick-slip tester, and the noise risk index was measured when the pieces were rubbed together three times at an amplitude of 20 mm under the conditions of 23°C, 50% RH humidity, 5 N load, and 1 mm / second speed. A higher noise risk index indicates a greater likelihood of squeaking noise. Because this test method evaluates the material after heat aging, it is also possible to evaluate the persistence of the squeaking noise reduction effect.

[0193] <Evaluation of Radio Wave Characteristics> (Measurement of relative permittivity and dielectric loss tangent (tanδ) at a frequency of 28 GHz) A test specimen with a diameter of 50 mm and a thickness of 0.3 mm was prepared by press molding a pellet of thermoplastic resin composition. Using a resonator (manufactured by Keysight Technologies) and measuring instruments (PNA network analyzer N5227A, millimeter-wave controller N5261A), the relative permittivity and dielectric loss tangent (tanδ) of this test specimen were measured at frequencies from 12 to 60 GHz using the balanced disk resonator method (BCDR method), and an approximate curve was created. Based on this data, the value at a frequency of 28 GHz was determined. (Measurement of relative permittivity and dielectric loss tangent (tanδ) at a frequency of 77 GHz) The relative permittivity and dielectric loss tangent at a frequency of 77 GHz were measured using the cutoff cylindrical waveguide method (JIS R1660-1) with a test specimen measuring 10 mm (length) x 10 mm (width) x 0.244 mm (thickness) cut from a molded product obtained by injection molding of a pellet of thermoplastic resin composition. In the above measurement, the frequency is determined by the thickness of the test specimen and the relative permittivity, so the thickness of the molded product used as the test specimen was set to 0.3 mm or 0.244 mm for the measurement. In each frequency measurement, 10 test specimens were prepared and measured, and the average value of each measurement result was recorded.

[0194] For use as millimeter-wave transparent resin components such as millimeter-wave radomes, the relative permittivity at a frequency of 28 GHz is 2.8 or less, particularly 2.5 or less, and the dielectric loss tangent (tanδ) is 5 × 10⁻¹⁰. －３ The following, especially 3 x 10 －３ The following is preferable. Furthermore, the relative permittivity at a frequency of 77 GHz is 2.7 or less, particularly 2.5 or less, and the dielectric loss tangent (tanδ) is 4 × 10⁻¹⁰. －３ The following, in particular, 2.7 × 10 －３ The following is preferable:

[0195]

[0196]

[0197]

[0198]

[0199] Tables 2 to 5 show that Examples II-1 to 15, which incorporate the graft copolymers (A-1) to (A-9) of the present invention, exhibit excellent compatibility with other thermoplastic resins, resulting in no delamination of the tensile fracture surface, superior impact resistance, heat resistance, appearance, and noise suppression effects. Furthermore, they possess radio wave characteristics equivalent to those of the polyphenylene ether resin compositions of Comparative Examples II-1 to 5, which are known to have low dielectric constant and dielectric loss tangent, and the modified polyphenylene ether resin of the Reference Example.

[0200] In contrast, Comparative Examples II-1 and II, which do not contain the graft copolymer (A) of the present invention, are inferior in impact resistance and creaking noise suppression effect. Of Comparative Examples II-3 to II-5, which contain graft copolymers (A'-10) to (A'-12) that do not fall under the present invention, Comparative Example II-3 is inferior in creaking noise suppression effect and appearance. Comparative Examples II-4 and II-5 also have problems with delamination of the tensile fracture surface due to their inferior compatibility with other thermoplastic resins. The commercially available m-PPE in the reference example does not provide a creaking noise suppression effect.

[0201] Molded articles made from the thermoplastic resin composition of the present invention exhibit excellent surface appearance, impact resistance, fluidity, and heat resistance, while also achieving a low specific gravity. Furthermore, they do not cause defects such as delamination, and exhibit superior functionality in areas such as noise suppression, as well as possessing radio wave properties (dielectric properties). Therefore, molded articles of the present invention can be suitably used as components for automobile parts, electrical and electronic equipment parts, industrial parts, and household electrical appliances. In particular, because molded articles of the present invention exhibit excellent radio wave properties in the high-frequency band and also have a superior noise suppression effect, they can be suitably used as components for high-speed communication equipment, and are especially useful as components for vehicle-mounted high-speed communication equipment subjected to vibration. Specifically, they can be used in housings such as radomes, antennas, connectors, switches, filters, converters, couplers, circulators, isolators, capacitors, inductors, coils, resonators, FPCs (Flexible Printed Circuits), etc. However, the applications of molded articles of the present invention are not limited to these.

[0202] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible within the scope of achieving the effects of the invention. This application is based on Japanese Patent Application No. 2025-030461, filed on 27 February 2025, which is incorporated herein by reference in its entirety.

Claims

1. A graft copolymer (A) obtained by graft copolymerizing a monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of an olefin-based rubbery polymer (a1), wherein the nitrogen element content in 100% by mass of the graft copolymer is greater than 0% by mass and 1.5% by mass or less.

2. The graft copolymer (A) according to claim 1, wherein the olefin-based rubbery polymer (a1) comprises an ethylene-α-olefin copolymer and / or an ethylene-α-olefin-nonconjugated diene copolymer.

3. The graft copolymer (A) according to claim 1, obtained by graft copolymerizing 90 to 10 parts by mass of monomer component (a2) containing an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of 10 to 90 parts by mass of the olefin-based rubbery polymer (a1) (provided that the total of the olefin-based rubbery polymer (a1) and monomer component (a2) is 100 parts by mass).

4. A thermoplastic resin composition comprising the graft copolymer (A) described in claim 1 and another thermoplastic resin (B) other than the graft copolymer (A).

5. The thermoplastic resin composition according to claim 4, wherein the content of the olefin-based rubbery polymer (a1) in 100% by mass of the thermoplastic resin composition is 2 to 30% by mass.

6. The thermoplastic resin composition according to claim 4, wherein the nitrogen element content in 100% by mass of the thermoplastic resin composition is greater than 0% by mass and 6.0% by mass or less.

7. The thermoplastic resin composition according to claim 4, comprising 1 to 50 parts by mass of the graft copolymer (A) and 50 to 99 parts by mass of the thermoplastic resin (B) (provided that the total of the graft copolymer (A) and the thermoplastic resin (B) is 100 parts by mass).

8. The thermoplastic resin composition according to claim 4, wherein the thermoplastic resin (B) comprises one or more selected from the group consisting of polyphenylene ether resins, polystyrene resins, polycarbonate resins, polyacrylic resins, polyamide resins, and polyester resins.

9. A molded article comprising the thermoplastic resin composition according to any one of claims 4 to 8.

10. A component for high-speed communication equipment, comprising the molded article described in claim 9.

11. A radome comprising the molded article described in claim 9.

12. A millimeter-wave radome comprising the radome described in claim 11.

13. A millimeter-wave radar comprising a millimeter-wave radome as described in claim 12.

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